Redox active ionic liquid as efficient mediator and solvent for visible light-driven B12 catalytic reactions

Abstract

The redox active ionic liquid, 1-ethyl-4-(methoxycarbonyl)pyridinium bis(trifluoromethanesulfonyl)amide (RIL), was synthesized from its iodide form by an anion exchange reaction of Li(NTf2) with viscos liquid (η = 122 cP at 25 °C) and characterized by NMR, IR, and elemental analysis. The compound showed reversible redox couples at −0.65 V and −1.48 V vs. Ag/AgCl and worked as an electron mediator in the B12 complex/[Ru(bpy)3]Cl2 photosensitizer catalytic system under visible light irradiation. The catalytic efficiency in the RIL was higher than those in DMF, MeOH, and the redox inactive ionic liquid, 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)amide. Keywords: Ionic liquid, Photosensitizer, Redox active, Visible light, Vitamin B12